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Anyone opinions using E85 for Track Days?

It may be sooner than later... Hypothetical, I might know a guy that is already running the clear stuff, has a jump on the competition with a runner vehicle and might be interested in an East coast partnership.😉
Mark I heard that a truck stop/gas station on Neville Island has the highest and consistent E85 in the Pittsburgh area.
 
Mark I heard that a truck stop/gas station on Neville Island has the highest and consistent E85 in the Pittsburgh area.
Cool. There are 3 speedways close to me. I have tested the summer and winter blend a few times at the closest one. Both blends have been really consistent. Winter was at 70ish and summer 84-85. I now have the tunes for 92, E85 and a fuel drain and would like to run the 85 at the track but no trailer "yet" so can only carry 10 gallons. With a 45-55 min turnaround time to the closest E85 station to the track it's just too much between sessions. I have to say running the 92 tune and not eating o2 sensors, not worrying about where I can fill up next and the increase in milage is nice.
With only a few hp and a bit more torque the 85 is night and day though. It just feels like there is better throttle response and pull. IDK maybe some of that is in my head since getting used to the car... I'm weird and do miss the 85 smell.

It smells fast! 😂
 

Boone

Professional Thread Killer
I ran VIR with 77% ethanol in the tank this past weekend. My car fell flat on its face at too in and came on lack gangbusters when it came alive. Definitely not the magic pill I was hoping for. I think I can get it worked out, but I believe it will require logging 93 and E85 runs in similar situations and tweaking the fuel curve.

I put 3/4 tank of 93 in the car (was E20 in the tank), and the issue went away. To be continued...
 
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I ran VIR with 77% ethanol in the tank this past weekend. My car fell flat on its face at too in and came on lack gangbusters when it came alive. Definitely not the magic pill I was hoping for. I think I can get it worked out, but I believe it will require logging 93 and E85 runs in similar situations and tweaking the fuel curve.

I put 3/4 tank of 93 in the car (was E20 in the tank), and the issue went away. To be continued...
Why don’t you call Shaun at AED, he has the correct tune for that setup.
 

PaddyPrix

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I ran VIR with 77% ethanol in the tank this past weekend. My car fell flat on its face at too in and came on lack gangbusters when it came alive. Definitely not the magic pill I was hoping for. I think I can get it worked out, but I believe it will require logging 93 and E85 runs in similar situations and tweaking the fuel curve.

I put 3/4 tank of 93 in the car (was E20 in the tank), and the issue went away. To be continued...
I'd be very curious to hear more about this. For me, I only ran the flex to a point where I knew I had at least 70% ethanol in the tank, and flashed it to a race e85 tune, and the difference was absolutely night and day, a completely different car. From the sounds of it, were you still on the flex tune at the track?
 
So you if you have to ditch the flex-fuel tune for the track, what‘s the use of getting a flex-fuel tune? I thought it sensed and optimized whatever fuel mix was in the tank?
 

PaddyPrix

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So you if you have to ditch the flex-fuel tune for the track, what‘s the use of getting a flex-fuel tune? I thought it sensed and optimized whatever fuel mix was in the tank?
That's not my understanding at all, our computers aren't that smart. From what I know of the SCT and other tunes, they don't have some auto-learn function where they'll start continually pushing boundaries and back off timing advance or whatever to optimize your power... that's something your tuner does when they're playing and testing things out on the dyno or from the datalogging files you've sent to them.

My understanding is that the purpose of the flex is, for when you're trying to run out the last of regular dino gas in the tank. So let's say you drive to the track, and there's an e85 nearby but you still have half a tank in it. You're not really going to just suck it out, so 7 gallons of 91 (E0-E10) and 7 gallons of e85 (E85) give you an EtOH of 42.5%, which isn't optimal. However, on the next e85 fill-up you should have trace amounts of regular gas, supposing you take it down to fumes or let's say 1 gallon, which then 1 gallon of E0 + 14 gallons of E85, and assuming it's true e85 of 85% ethanol, you've then got a tank with EtOH of about 80%. Again, assuming that the gas you're putting in is quality e85, which in some places is very dependable (Propel in SoCal is fantastic, it's been 86-88% every single time) but depending on seasonality or just crappy quality, could be anywhere from 51-83% like it usually stays on a sticker or handle nearby. Let's assume the worst and say that it's e50, you're going to have problems with a full race tune which assumes you've got a minimum of 70% EtOH. That exact number might vary per tuner, and if you've got an e98 tune, it's even higher.

For the EtOH minimum, it's not so much optimization, but the car does have control over the fuel and how much it is to perform optimally. Gasoline air to fuel stoich is 14.7:1, so if it's being given ethanol which is 9.85:1, the wideband o2 sensor seeing 9.85:1 would think it's running super, super rich, and I'm guessing the car would start cutting fuel in an attempt to get back to where it thinks it'd be happy. Again, that just might be on the stock tune, whereas an aftermarket might give it an additional thing to think about, where it'd ask it to sample the EtOH% as well, and depending on where that stands, to perform slightly differently. If the computer is differently programmed and told that it's got essentially 108-115 octane in there, they can start pushing the limits, bumping up the timing, and having fun knowing that they've got more potential at their disposal.

Should you be double duty your car and head back home, perhaps e85 isn't something that is all along your trip back, so that's again where Flex would come in nicely, as this time you're burning off the excess e85 as you return back to pump gas, and after a tank or two, could even go back to a decent street tune which is all about the 87-91 stuff... or perhaps there's an e85 pump and you'll go have fun ripping some off at night, who knows, stay flex then.

As for me, I ran the flex for one session, and it felt just a little peppier than the ol' track setting. The e85 race tune woke the car the hell up, flying through the powerband from 4k to 8k, whereas before it was like 5.5 to 7. It's probably only 20-30hp, but it felt like a whole lot more, and some lap times to prove it.

That's my .02, just some dude on the internet who runs e85 and got a near perfect on his Math SAT.
 
That's not my understanding at all, our computers aren't that smart. From what I know of the SCT and other tunes, they don't have some auto-learn function where they'll start continually pushing boundaries and back off timing advance or whatever to optimize your power... that's something your tuner does when they're playing and testing things out on the dyno or from the datalogging files you've sent to them.

My understanding is that the purpose of the flex is, for when you're trying to run out the last of regular dino gas in the tank. So let's say you drive to the track, and there's an e85 nearby but you still have half a tank in it. You're not really going to just suck it out, so 7 gallons of 91 (E0-E10) and 7 gallons of e85 (E85) give you an EtOH of 42.5%, which isn't optimal. However, on the next e85 fill-up you should have trace amounts of regular gas, supposing you take it down to fumes or let's say 1 gallon, which then 1 gallon of E0 + 14 gallons of E85, and assuming it's true e85 of 85% ethanol, you've then got a tank with EtOH of about 80%. Again, assuming that the gas you're putting in is quality e85, which in some places is very dependable (Propel in SoCal is fantastic, it's been 86-88% every single time) but depending on seasonality or just crappy quality, could be anywhere from 51-83% like it usually stays on a sticker or handle nearby. Let's assume the worst and say that it's e50, you're going to have problems with a full race tune which assumes you've got a minimum of 70% EtOH. That exact number might vary per tuner, and if you've got an e98 tune, it's even higher.

For the EtOH minimum, it's not so much optimization, but the car does have control over the fuel and how much it is to perform optimally. Gasoline air to fuel stoich is 14.7:1, so if it's being given ethanol which is 9.85:1, the wideband o2 sensor seeing 9.85:1 would think it's running super, super rich, and I'm guessing the car would start cutting fuel in an attempt to get back to where it thinks it'd be happy. Again, that just might be on the stock tune, whereas an aftermarket might give it an additional thing to think about, where it'd ask it to sample the EtOH% as well, and depending on where that stands, to perform slightly differently. If the computer is differently programmed and told that it's got essentially 108-115 octane in there, they can start pushing the limits, bumping up the timing, and having fun knowing that they've got more potential at their disposal.

Should you be double duty your car and head back home, perhaps e85 isn't something that is all along your trip back, so that's again where Flex would come in nicely, as this time you're burning off the excess e85 as you return back to pump gas, and after a tank or two, could even go back to a decent street tune which is all about the 87-91 stuff... or perhaps there's an e85 pump and you'll go have fun ripping some off at night, who knows, stay flex then.

As for me, I ran the flex for one session, and it felt just a little peppier than the ol' track setting. The e85 race tune woke the car the hell up, flying through the powerband from 4k to 8k, whereas before it was like 5.5 to 7. It's probably only 20-30hp, but it felt like a whole lot more, and some lap times to prove it.

That's my .02, just some dude on the internet who runs e85 and got a near perfect on his Math SAT.
I believe you‘re a math wiz, because I have a headache now. 😬 Thanks very much for the detailed explanation - I’m trying to get my head around it In terms of practicality. I don’t know much at all about tuning in terms of hardware, software and usage.

I have a base 2017 GT with stock tune. I’m trying to decide between a 93 octane tune and a flex-fuel/E85 tune. If I were to get a Flex Fuel tune, in order to optimize the car’s performance on the track, I’d also need (at least) one other tune installed? A full-race tune for track when I’ve got the good stuff, 77 or higher, in the tank? Is that correct?But if I’ve got ONLY the flex fuel tune, and the only fuel I can get is pump 93, I’m good to go both on street and track?

So you have multiple tunes installed and you use a handheld unit, plugged into the car, to change tunes based on what you’ve got in the tank?

If I only had the flex-fuel tune and track the car with an 80% mixture, how will it perform compared to a 93 octane tune?

I’ve a low tolerance for hassle, so want to figure out if the added power is worth it. Thanks again!
 
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5,765
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I believe you‘re a math wiz, because I have a headache now. 😬 Thanks very much for the detailed explanation - I’m trying to get my head around it In terms of practicality. I don’t know much at all about tuning in terms of hardware, software and usage.

I have a base 2017 GT with stock tune. I’m trying to decide between a 93 octane tune and a flex-fuel/E85 tune. If I were to get a Flex Fuel tune, in order to optimize the car’s performance on the track, I’d also need (at least) one other tune installed? A full-race tune for track when I’ve got the good stuff, 77 or higher, in the tank? Is that correct?But if I’ve got ONLY the flex fuel tune, and the only fuel I can get is pump 93, I’m good to go both on street and track?

So you have multiple tunes installed and you use a handheld unit, plugged into the car, to change tunes based on what you’ve got in the tank?

If I only had the flex-fuel tune and track the car with an 80% mixture, how will it perform compared to a 93 octane tune?

I’ve a low tolerance for hassle, so want to figure out if the added power is worth it. Thanks again!
I have 3 seperate tunes for 91, 100 and e85.
On my blown stroker 3 valve e85 was worth 100 whp and 100 wtq.
On my NA coyote it is only worth about 12 whp. NA motors do not benefit nearly as much as there is no boost to add. However, you still benefit from the added cooling, some hp gains and best of all, lower cost. I don’t even wanna know what 100 octane race gas costs these days…..my fuel is still 3 bucks a gallon and that alone makes it worth it to me. When the car was still street legal and I had to travel I would carry extra fuel Jugs in The trunk.
 
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PaddyPrix

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I don’t even wanna know what 100 octane race gas costs these days…..my fuel is still 3 bucks a gallon and that alone makes it worth it to me. When the car was still street legal and I had to travel I would carry extra fuel Jugs in The trunk.
5 gallon pail of Sunoco 100 was $75 the other weekend, and at the track pump it depends, but I recall 108 at ACS was $12.50. Precisely why I'm e85 till I die.
 

Boone

Professional Thread Killer
The system I have on my '05 GT is true flex fuel. If I have E50 in the fuel rail, it adjusts the fuel delivery accordingly. Timing is not factored in (see our discussions about flame front speeds previously).

Per the manufacturer, I am supposed to tune for 93 octane and change blends at will. No need to run down to empty on 93 or change tunes at the pump. More importantly, no issue with going lean when the ethanol content is not up to snuff. I'm not completely satisfied yet with the tune. I'm going to put a wideband on my car to monitor the F/A ratio in regards to Lambda to try to monitor the tip in issue on high ethanol. I had to make a lot of changes at once with my current setup, and we know how that muddies the waters when tracking down an issue.

Currently, I'm running great on E20. I may bump the ethanol content up little by little to see where the tip in issue starts. If I need a separate track tune for E85, I'll go that route, but I don't want to go down that path just yet. We'll see if we can work out the flex fuel system without unacceptable compromises.
 
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Recently switched to E85 and while I knew it was going to provide some cooling I was surprised how long the car took to heat up. I haven't had it on track yet but looking forward to seeing how it does. The additional power is nice too, the Gen3 coyotes pick up a good bit of low end grunt on corn.
 
5,765
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Exp. Type
W2W Racing
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Pleasanton: 1/2 way between Sonoma and Laguna Seca
Recently switched to E85 and while I knew it was going to provide some cooling I was surprised how long the car took to heat up. I haven't had it on track yet but looking forward to seeing how it does. The additional power is nice too, the Gen3 coyotes pick up a good bit of low end grunt on corn.
I was talking with Shaun about this a while back. Apparently the direct injection on the gen 3 benefits way more from e85 than the port injection of earlier models. I saw 12 hp going from 91 to e85. We don’t get nearly the bump the gen 3’s do, but still worth the trouble for all the same reasons.
 

Bill Pemberton

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As usual do keep in mind if your car is under warranty, or if you want to extend your warranty, this is not a choice. Your car will lose coverage once a tune is put in or you use E-85. There are advantages that you are reading, but this is the major disadvantage for many members, so please keep this in mind.
 
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2 main issues
The biggest is mileage.
U looking about 2-3 mpg on track
In hpde or TT is not an issue. In longer racing you need a fuel.
The second is : fuel starvation increases in left corners and u need to run always above 3/4 tank .
So 40lbs ish minimum more weight. That might nul.the hp.gain.
So a fuel surge tank might be necessary
But again depends of usage and your actual speeds.
 
Ale how do you see the fuel starvation any different between E85 and regular gas? before my in-tank transfer pump I'd starve at 3/4 tank which I would reach by the end of a flat out 20min session anyways. So at least for me the extra burn rate of E85 does not induce starvation earlier, the car was starving already on regular gas.
 

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